1. Field of the Invention
This invention relates to a device used for evacuation from a high building in case of a fire, particularly to a slow-descending device for evacuation which enables a person to descend safely from a high place, and more particularly to a portable slow-descending device for evacuation which anybody can carry for personal use.
2. Description of Related Art
Although a building or other type of structure is usually equipped with evacuation devices, they are not provided in every room, but are provided only in selected rooms, or at particular sites of one or more corridors. In the case of a fire, for example, it is very likely that many people may rush to each evacuation device and cause a panic, or it is even likely that fire or smoke may prevent people from reaching any of the places where those devices are provided, and to use them.
An evacuation device having a lifeline formed from a metal wire is heavy and unsuitable for portable use. Moreover, it has a limit in the distance along which it enables a person to descend, i.e., the height of the building from which it enables the person to descend. Its use is limited to a low building having a height of, say, 30 m at a maximum. There is every likelihood that a person using a lifeline formed of a metal wire to escape from a high building may be suspended in the air. Thus, it has only a limited scope of use. There has also been proposed a device which includes a wire having a smaller diameter and a longer length. However, these devices are not only heavy, but are also subject to rusting by salt or moisture. Therefore, it is unsuitable as a device of the kind under consideration which is required to be semipermanently useful without undergoing any substantial change in quality.
There has also been proposed a device which includes a lightweight rope formed from a non-metallic material. It is, however, likely that when a load is applied to the rope extending down from a reel or the like on which it is wound, it may be deformed and caught between coils thereof on the reel, resulting in a failure of the rope to be smoothly unwound and the failure of the reel to turn smoothly, and a person who is being rescued may, therefore, be suspended in the air.
There are known various types of mechanisms for slow-descending devices. A device employing a hydraulic system is likely to have a greatly varying descending speed which may depend on the weight of a person who is rescued. When it is used in a very cold place, oil is likely to solidify. Moreover, a change in quality of oil or its leakage is likely to occur.
It is an object of this invention to provide a portable slow-descending device which can overcome the drawbacks of the devices described hereinabove.